1. Field of Invention
This invention relates briefly to welded constructions and more specifically to a welded screed construction and a method of making such construction.
2. Background Art
One extensively used form of portable vibrated screed used for screeding concrete between two forms has a frame comprising a network of individually cut metal rods extending between a ridge member in the form of a tube or plate at the top of the screed and front and rear, spaced apart, screed blades at the base of the screed. Individual rods are welded to the ridge member at one end and to one of the screed blades at the opposite end to form the sides of an open screed frame of triangular cross section. Other rods are welded to and between the blades to form the base. U.S. Pat. No. 4,249,327 illustrates use of what are typically individually cut and welded metal rods to form the frame of a portable vibrated screed using individual air vibrators. While not illustrating a rod type frame, U.S. Pat. No. 4,253,778 illustrates another type of widely used portable vibrated screed in which the vibration is achieved by a vibrating shaft. This type of shaft vibrated screed also lends itself to having the frame formed of rods. Other portable vibrated screeds use individual electric vibrators rather than individual air vibrators.
The ends of the individual rods which are welded to the ridge member do not tend to break at the weld joints. However, the ends of the individual rods forming the side of the frame and welded to the screed blades to tend to break loose at the weld joints due to the vibration and severe service conditions imposed on the blades. The entire screed then has to be taken out of service and repaired.
The object of the present invention is thus to provide an improved screed construction for a portable vibrated screed using an open network of rods to form the frame but with a construction and method of construction that reduces and substantially eliminates any opportunity for the rod welds to break loose from the screed blades. Other objects will become apparent as the description proceeds.